Typewriting machine



Nov. 24, 1925.

W. F. HELMOND TYPEWRITING MACHINE Filed Feb. 1.

1922 2 Sheets-Sheet 2 vm lyw Patented Nov, 24, 1925.,

UNITED STATES.

WILLIAM F. HELMOND, OF HARTFORD, CONNECTICUT, ASSIGNOR TO UNDERWOOD PATENT OFFICE.

TYPE'WRITER COMPANY, OF N EW YORK, N. Y., A CORPORATION .OF DELAWARE.

TYPEWRITING MACHINE.

Application filed February To all whom it may concern:

Be it known that I, WILLIAM F. HELMoNo, a citizen of the United States, residing in Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Typewriting Machines, of which the following is a specification.

This invention relatesto type actions for typewriting machines, and a feature of the invention is to control the character of the type impressions and to reduce the noise caused by the type-bars striking the platen.

In carrying out the invention, a stop is employed to arrest the key-levers before the type-bars strike the platen, and lost motion is provided in the connection between each key and the type-bar to allow the typebar to continue in its movement, independently of the keys, by momentum, and print.

With this lost-motion connection, the typebars strike the laten with less force than would result if they could be followed up all the way to the platen by the pressure on the key-levers.

Thus the inkedtype impressions on the paper may be lightened and sharpened and noise of the type blows may be reduced.

Thestop for the key-levers may be adjustable to vary the distance of the independent movement of the type-bars. This distance may be decreased to cause the type-bars to.

strike with a greater force against the platen when manifolding. When it is desired to make a very large number. of manifold copies, the stop may be thrown entirely out of action.

Another feature of the invention is to increase the promptness of the return stroke of the escapement mechanism, so as to increase speed of operation and evenness of letter-spacing. This is brought about by the partial independent return movement of the type-bar at the initial art of its return stroke, while the fingerv o the operator is momentarily holding the key at the bottom of its stroke.

The stop may be regulated to a point to 1, 1922. Serial No. 533,222.

secure the clearest impressions of the type upon the work-sheet. Moreover, by varying the position of the stop, the depth of color of the inked impressions on the sheet may be varied at will, which is a desideratum in typing in the addresses on mimeographed and multigraphed circulars, .where it is desired that both the address and the body of the circular be typewritten.

. Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a side view of an Underwood type action and part of the carriage-escapement mechanism, illustrating the invention in connection therewith, and showing the parts in normal positions.

Figure 2 shows the type-bar moved by the key-lever to the position from which it travels independently to the platen.

Figure 3 shows the type-bar operated and the key-lever stop rendered ineffective.

Figure 4 is a fragmentary sectional front view, showing how the key-lever stop is supported inthe machine frame.

Key-levers 10 when depressed swing about fulcrums 11 against the tension of return springs 12 to rock bell-cranks 13 about their pivots 14 and swing type-bars 16 upwardly and rearwardly to rint against the front side of a platen 1 The type-bars are pivotall supported on a curved rod 18 in a typear segment 19, and are guided in radially-disposed slots 20 to a common printing'point and strike the usual type-bar arrester 21 on the segment.- Each type-bar is provided with a heel 22 to engage a universal bar 23 to push a universal frame 23 rearwardly, and, by means of a cross-bar 24 on said universal frame, swing the upper end of a dog-rocker 25 rearwardly to disengage a loose dog 26 from the usual escapement wheel 27 and move a fixed dog 28 into the path of said wheel, said escapement wheel having the usual connection with a carriage, not shown, which supports the platen 17. The usual return springs, not shown, may be employed to restore the dogrocker and the universal frame to normal positions, the feeding of the carriage being efl'ected upon the return stroke of the dogrocker, or, in other words, when the loose dog 26 re-engages the escapement wheel.

The key-levers 10 are arrested by a stop 29, engaged by shoulders 30,.before the typebars reach the platen. Lost motion is provided in thejconnection between each keylever 10 and each bell-crank 13, there being a stud 31 on each key-lever to engage between two prongs 32 and 33 formed by a slot 33 in each bell-crank l3, and each slot being wider than the diameter of the stud,

thus producing the 10st motion. Consequently, the key-lever moves idly for a slight distance from the Figure 1 position until the stud reachesthe lower prong 32 of the bell-crank. The key-lever then drives the type-bar to the Figure 2 position, where the key-lever engages the stop 29 and is consequently arrested. It will be seen thatin this position the upper prong of the bellcrank is out of engagement with the studon the key-lever, and consequently the typebar is free to continue in its movement, under the influence of its attained momentum, to strike against the platen. By arresting the key-lever, the force is somewhat broken, and consequently the type-bar prints against the platen with less noise. Since the "distance of travel of the key-lever in the location of the stop 29 is very slight, any sound which might be produced by the contact of the key-lever with said stop is practically negligible. Upon the return stroke of the key-lever, the stud engages the upper prong 83 of the bell-crank to rock the latter and swing the type-bar back to its normal position. I

The formof stop 29 herein shown is cylindrical and is pivotally and eccentric- 0. 1y su ported by trunnions 34 at its ends pivoted 1n the machine frame .35, so that the stop may be adjusted to vary the distance between it and the engagingshoulders 30 of the keylevers to change the force with which the type-bars strike the platen when making a greater or smaller number of manifold copies. The stop 29' may be rendered entirely ineffective by rotating it to the position shown in Figure 3, when it is desired to type through an extremely thick pack of manifold sheets.

To manipulate the key-lever stop, there is provided at its right-hand end a finger-wheel 36 which may be secured to the trunnion 34. Said stop may be held in its various positions of adjustment by means of a spring detent 37 engaging in notches 38 of a sector 39 secured tothe trunnion 34, said sector being herein provided with four notches settable to four positions and engaging with two stops 40 and 41 to limit the rotary moveinent of the key-lever stop in its two exsufficient to allow the return of the universal bar and consequently of the escapement devices, thus affording an early start in the letter-spacing movement of the carriage, and avoiding any undue delay which may otherwise be caused by the key-lever.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typewriting machine, the combination of a platen, key-levers, type-bars, bellcranks connecting the key-levers with said type-bars, a revoluble stop disposed beneath the key-levers to arrest them, each bellcrank having a lost-motion connection with its key-lever to allow the type-bar to travel by its attained momentum to print against the platen after the keylever has been arrested, and means to adjust said stop about its axis to vary the distance the type-bar may travel after the key-lever has been arrested. v

2. In a typewriting machine, the combination of a platen, type-bars, key-levers, bellcranks connecting said type-bars with said key-levers, the bell-cranks having slots, studs on the key-levers to engage in the slots, the width of the slot of each bell-crank being slightly greater than the diameter of the stud of the associated key-lever to afford a lost-motion connection between the bellcrank and the key-lever, and a stop to arrest the key-lever before the type-bar strikes the platen, the lost motion being provided so that the type-bar by its attained momentum is caused to continue in its movement and print against the platen after the keylever has been arrested.

3. In a typewriting machine, a carriage, a platen therein, type-bars carrying types to print against the platen, key-levers to actuate the type-bars, means operatively connecting the key-levers and type-bars, comprising loose pin-and-yoke connections, and means to arrest each key-lever on the printing stroke of its type-bar, the loose pin-andyoke connection being effective to permit the type-bar to travel by its attained momentum to print against the platen after its keylever has been arrested, and to cause the type-bar to pick up the key-lever on its return stroke and return to normal position concurrently with the key-lever and in op-' the types to complete their printing strokes erative relation to it. by momentum, by reason of looseness in the 10 4. The combination with a platen, of a set "connections between said arresting meens of type-bars, operating keys, individual conand the type-bars, and means for mov ng 5 nections between the keys and the type-bars, l llqstlng means to meifeetlve position neans common to the keys to engage and and b0 dlfifll'nt WOIklDg POSIUOIIS, to vary arrest certain portions of said connections the yp blowsas the types approach the platen, to permit WILLIAM F. HELMOND. 

